public override IEnumerable <KeyValuePair <K, int> > CompareNonIndexedKeyWithKey <K, T>(
DbColumn key, DbColumn column, TokenType comparer, T value)
{
if (column.Indexed || column.Table.Multikey)
{
throw new ArgumentException($"Column {column} must be un-indexed, and belong to a One-Key table");
}
//get the key column, index
var keyColumn = column.Table.Key;
int keyColumnIndex = column.Index;
K keyValue = default(K);
var keyCount = 0;
//read indexer offsets in their order
using (var keyReader =
new io.BinaryReader(
io.File.OpenRead($"{key.Table.Database.BinaryPath}\\{key.Hash}.offset")))
{
//amount of keys
keyCount = keyReader.ReadInt32();
var count = Table.Count;
var initialCount = column.Index;
var buffer = new byte[sizeof(UInt64)];
var bytes = Table.RowMaskLength;
var mainMask = Table.RowMask;
int columnIndex = 0;
int columnSize = 0;
int bytesToSkip = 0;
ulong bitMask = 0;
ulong recordMask = 0;
void SKIP(int cnt)
{
while (cnt-- > 0)
{
if ((recordMask & bitMask) == 0)
{
if (columnIndex == keyColumnIndex)
{
//read Key value into: keyValue
keyValue = GetColumnValue <K>();
}
else
{
//SKIP
//not null value, add according to column type
if (columnSize == 0)
{
throw new ArgumentException("unsupported type size");
}
else if (columnSize > 0)
{
bytesToSkip += columnSize;
}
else
{
//string, read length, and add chars
reader.BaseStream.Position += bytesToSkip;
//read new bytes to skip
bytesToSkip = reader.ReadByte();
}
}
}
bitMask >>= 1;
columnSize = ColumnTypeSizes[++columnIndex];
}
//position reader
if (bytesToSkip > 0)
{
reader.BaseStream.Position += bytesToSkip;
}
}
C GetColumnValue <C>()
{
//for string, read length byte
var size = (columnSize < 0) ? reader.ReadByte() : columnSize;
//create buffer
var columnBuffer = new byte[size];
//read it
reader.Read(columnBuffer, 0, size);
//convert it to generic value
return(columnBuffer.BitConvertTo <C>());
}
for (var ndx = 0; ndx < keyCount; ndx++)
{
var offset = keyReader.ReadInt32();
//point to record offset
reader.BaseStream.Position = offset;
//copy main mask
bitMask = mainMask;
//read record mask
reader.Read(buffer, 0, bytes);
recordMask = BitConverter.ToUInt64(buffer, 0);
//developer only
var binary = Convert.ToString((long)recordMask, 2);
//
columnSize = ColumnTypeSizes[columnIndex = 0];
bytesToSkip = 0;
//skip initial columns if any
if (initialCount > 0)
{
SKIP(initialCount);
}
//read column value to compare
var columnValue = GetColumnValue <T>();
if (comparer.Compare <T>(columnValue, value))
{
if (keyColumnIndex > columnIndex)
{
//key not read yet
SKIP(keyColumnIndex - columnIndex - 1);
//read Key value into: keyValue
keyValue = GetColumnValue <K>();
}
yield return(new KeyValuePair <K, int>(keyValue, offset));
}
}
}
}
/// <summary>
/// Expensive non-indexed column comparison by a constant value
/// </summary>
/// <typeparam name="T">type of column</typeparam>
/// <param name="key">table key</param>
/// <param name="column">column to compare</param>
/// <param name="comparer">comparison operator</param>
/// <param name="value">constant value</param>
/// <returns></returns>
public override IEnumerable <int> CompareNonIndexedKey <T>(
DbColumn key, DbColumn column, TokenType comparer, T value)
{
//THIS CANNOT BE TOGETHER WITH CompareNonIndexedKeyWithKey BECAUSE
// RETURNING KEY MAKE AN EXTRA LOAD
var keyCount = 0;
//read indexer offsets in their order
using (var keyReader =
new io.BinaryReader(
io.File.OpenRead($"{key.Table.Database.BinaryPath}\\{key.Hash}.offset")))
{
keyCount = keyReader.ReadInt32();
var count = Table.Count;
var initialCount = column.Index;
var buffer = new byte[sizeof(UInt64)];
var bytes = Table.RowMaskLength;
var mainMask = Table.RowMask;
int columnIndex = 0;
int columnSize = 0;
int bytesToSkip = 0;
ulong bitMask = 0;
ulong recordMask = 0;
//build column type translator
var columnTypeSizes = Table.ColumnTypes.Select(t => t.GetSize()).ToArray();
void SKIP(int cnt)
{
while (cnt-- > 0)
{
if ((recordMask & bitMask) == 0)
{
//not null value, add according to column type
var size = columnTypeSizes[columnIndex];
if (size == 0)
{
throw new ArgumentException("unsupported type size");
}
else if (size > 0)
{
bytesToSkip += size;
}
else
{
//string, read length, and add chars
reader.BaseStream.Position += bytesToSkip;
//read new bytes to skip
bytesToSkip = reader.ReadByte();
}
}
bitMask >>= 1;
columnSize = ColumnTypeSizes[++columnIndex];
}
//position reader
if (bytesToSkip > 0)
{
reader.BaseStream.Position += bytesToSkip;
}
}
T GetColumnValue <T>()
{
//for string, read length byte
var size = (columnSize < 0) ? reader.ReadByte() : columnSize;
//create buffer
var columnBuffer = new byte[size];
//read it
reader.Read(columnBuffer, 0, size);
//convert it to generic value
return(columnBuffer.BitConvertTo <T>());
}
for (var ndx = 0; ndx < keyCount; ndx++)
{
var offset = keyReader.ReadInt32();
//point to record offset
reader.BaseStream.Position = offset;
//copy main mask
bitMask = mainMask;
//read record mask
reader.Read(buffer, 0, bytes);
recordMask = BitConverter.ToUInt64(buffer, 0);
//developer only
var binary = Convert.ToString((long)recordMask, 2);
columnSize = ColumnTypeSizes[columnIndex = 0];
bytesToSkip = 0;
//skip initial columns if any
if (initialCount > 0)
{
SKIP(initialCount);
}
//read column value to compare
var columnValue = GetColumnValue <T>();
//compare
if (comparer.Compare <T>(columnValue, value))
{
yield return(offset);
}
}
}
}